From time to time, you may want to check vital statistics about an application running on your computer. E.g. Suppose you have the application ID for a process, e.g. obtained from Activity Monitor on a Mac, here’s an easy way to find out the command path used to start the process:

Have you ever felt the discomfort of having to log in twice into a server so you can run two applications simultaneously? Have you wondered if there could be an easier way? Or are you looking for an easy way to start a long process on a server, detach from it, and connect back to the same session from a different client? Well, there’s a solution for all your worries. It’s called tmux! tmux allows you split a terminal into several subsections. It also allows you start a session over ssh and log out while the session keeps running, then log in via ssh on a possibly different machine and resume your session. So, the client becomes more irrelevant. I’ll discuss how to do a few things using tmux.

How to start a new tmux session run the following

tmux new -s session-name

or run the following

tmux new

It’s recommended to use the first format as it gives your sessions more meaningful names.

To detach from a session, run the following:

Ctrl-b d

or run the following

tmux detach

To list sessions, use the command

tmux ls

Note that tmux uses Ctrl-b as a prefix for its operations by default. This can be changed though as tmux is highly configurable.

To attach to an existing session use the following:

tmux a

This attaches to the first available session. You can also use the following:

tmux a -t session-name

To attach to a named session.

When logged in to a session, you can split the window into panes.

To split the window vertically, use the following command:

Ctrl-b %

To split it horizontally use the command:

Ctrl-b "

To switch pane, use the command

Ctrl-b arrow key

To resize a pane use the following command:

Hold Ctrl-b, then hold an arrow key

To scroll up a page on OS X, press Ctrl-b then [. This will put you in scroll mode. You can then use arrow keys to go up and down. To move page by page while in scroll mode, using PageUp and PageDown keys. On a laptop without PageUp key, you can simulate it by pressing Cmd-Up Arrow. To exit scroll mode press q.